Spin Dynamics in a One-Dimensional Ferromagnetic Bose Gas

Abstract

We investigate the propagation of spin excitations in a one-dimensional (1D) ferromagnetic Bose gas. While the spectrum of longitudinal spin waves in this system is sound-like, the dispersion of transverse spin excitations is quadratic making a direct application of the Luttinger Liquid (LL) theory impossible. By using a combination of different analytic methods we derive the large time asymptotic behavior of the spin-spin dynamical correlation function for strong interparticle repulsion. The result has an unusual structure associated with a crossover from the regime of trapped spin wave to an open regime and does not have analogues in known low-energy universality classes of quantum 1D systems.

Quantum flutter of supersonic particles in one-dimensional quantum liquids

“…Our results provide an example of new physics induced by supersonic motion in a non-relativistic quantum system. Previous works on fast propagation in Bose gases assumed either a weakly coupled gas described by a set of noninteracting Bogoliubov excitations [15][16][17][18][19][20], or a strongly interacting system treated within a low-energy effective field theory approach [21][22][23]. In this paper we find that there are novel features that require both the strong coupling regime and a high energy impurity, thus going beyond the regime addressed in previous works.…”

Phase Transitions for a Collective Coordinate Coupled to Luttinger Liquids

“…In that case, special effects can potentially occur, as is clear from the static impurity case [16] and mobile ones coupled to single baths [17,18]. In particular, it was shown recently [19] that this led to a new universality class for the motion of the impurity, for which, in particular, subdiffusion can occur. This very rich situation was explored further.…”

Charge dynamics in half-filled Hubbard chains with finite on-site interaction

“…[4][5][6][7][8] In addition, ultracold atoms trapped in optical lattices have emerged as a new means to study coherent dynamics of 1D models, including integrable ones which are not realizable in condensed matter systems. 9 At the same time, significant progress has been achieved in developing analytical [10][11][12][13][14][15][16][17][18][19][20][21][22] and numerical [23][24][25] techniques to study dynamical correlation functions in the high energy regime where conventional Luttinger liquid theory 26,27 does not apply. Analytically, it is possible to compute exponents of power-law singularities that develop near thresholds of the spectrum of dynamical correlation functions at arbitrarily high energies.…”